A one-time-programmable OTP memory, also known as a “write-once” memory is a non-volatile memory wherein an erase function is typically not possible. In other non-volatile memories, such as Flash memories, the erase function may be possible but is typically time-consuming.
Both types of memories, as well as other types, may be used for counting events. For example, as each event happens, a bit in the memory may be set. To calculate the number of events that have occurred, the number of set bits in the memory is counted.